Historically, a NAF is a level of command below a MAJCOM (Major Command), and above one or more Wings or independent Groups. Over time their role has changed. Some NAFs were replaced with MAJCOMs, and some MAJCOMs were replaced with NAFs. In addition, some NAFs had dual-roles as MAJCOMs, as air components of Unified Commands, or as air components of Subunified or Combined Commands. In the U.S. Air Force reorganization of the early 1990s, NAFs were reorganized as tactical echelons providing operational leadership and supervision. In this new role, they were not management headquarters and did not have complete functional staffs. However, several NAFs continued to serve as air components of Subunified or Combined Commands. In these cases the NAF function was separate from the air component function, even though the commander was "dual hatted" as the commander of both organizations. The best example of this arrangement in recent history is Ninth Air Force, which doubles as United States Air Forces Central (USAFCENT), the air component of U.S. Central Command.
NAFs are typically commanded by a Major General. NAFs commanded by a Lieutenant General are typically those with a dual-role as air components of Subunified or Combined Commands, where their commander is "dual hatted" as the commander of both organizations.
In 2004 and 2005 the role of the NAF changed again. In this case, the NAF has essentially been eliminated as a tactical echelon. Instead, the distinct air component staff is being organized into a Warfighting Headquarters (WFHQ), and the former command responsibilities of the NAF are being assigned directly to the parent MAJCOM. The Air Force Component Numbered Air Force (C-NAF) Headquarters is the Air Force contribution to the Chairman of the Joint Chiefs of Staff direction that all combatant commands establish a Standing Joint Force Headquarters (SJFHQ). As a result, several NAFs have been deactivated, and some that remain are a NAF in name only. C-NAFs more correctly are a provisional air component headquarters for potential contingencies. In this role they are responsible for the in-place command and control elements, such as Air Operations Centers, along with other functions which previously belonged to the MAJCOM Operations Directorate.
The Fifteenth Air Force and Twenty-First Air Force were Numbered Air Forces, but have since been redesignated as Expeditionary Mobility Task Forces (EMTFs). The Sixteenth Air Force was inactivated and reconstituted as the 16th Air Expeditionary Task Force December 1, 2006. It is due to be inactivated in late April 2008. At the same time, a new NAF, Eighteenth Air Force, was established as the single NAF under AMC. Each EMTF is commanded by a Brigadier General and is responsible for supporting Air Mobility support for one or more geographic regions. In addition, the EMTF commander is pre-designated at the Director of Mobility Forces (DIRMOBFOR) for the Air Force Warfighting Headquarters the EMTF supports.
Numbered Air Forces at one time often included Air Divisions, but this organization has become obsolete and unused. The last Air Divisions were disbanded in 1991. Air Divisions were composed of two or more Wings or independent Groups.
